CCNA Voice Practice Tests – PSTN and Service Provider Networks (16-20)

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Topic 4 – PSTN and Service Provider Networks

Question 16
You are CCNA VOICE associate in Lead2pass.com. How many discrete call legs are needed to set up a call between the POTS phone attached to P4S-Router 1 and the phone in the PSTN?
A.3
B.4
C.6
D.7
Answer: B
Explanation:
A voice call over a packet network is segmented into discrete call legs. These are associated with dial-peers (a dial-peer is associated with each call leg). A call leg is a logical connection between two routers/gateways or between a router/gateway and an IP Telephony device and so forth.
Therefore, this voice call comprises four call legs, two from the perspective of the originating router/gateway and two from the perspective of the terminating router/gateway, as diagrammed below:

Question 17
Please choose the correct call leg to the proper locations ,provide call setup in both directions. Arrows may be used more than once, and not all may apply.
Explanation:
Then you need to work out how many call legs does this call take up. Now remembering our study we know that.
IP phone to Router = 1 call leg
Router into Voip Cloud = 1 call leg
Voip Cloud into Router = 1 call leg
Router to PSTN phone via PSTN Cloud = 1 call leg
This gives us 4 call legs for this call. Now just drop the arrows of the correct length into the target boxes. In this example you would only be using the small arrows four times.

Question 18
You are CCNA VOICE associate in Lead2pass.com. You place a phone call from ext1234 to ext 2010. Which inbound dial peer on P4S-CMERouter1 will be matched?
A.None, the call will drop
B.default dial peer 30
C.voip dial peer 30
D.default dial peer
Answer: D
Explanation:
This question is to examine the steps for inbound dial-peer matching.
1. Looking for the incoming called-number command to match the called number;
2. Looking for the answer-address command to match the calling number;
3. Looking for the destination-pattern command to match the calling number;
4. Looking for the POTS dial peer port configuration to match the voice port;
5. If no matches are available, the system uses the default dial peer.
As there is only one dial-peer on P4S-CMERouter1 and it is impossible to fulfill the former matching conditions. Therefore, the inbound dial peer matches the default dial-peer.

Question 19
You are CCNA VOICE associate in Lead2pass.com.Your company is migrating from a traditional PBX to a Cisco Unified Communications system. During migration process you need to provide common channel signaling connectivity to the PBX from the Cisco Unified Communications system. Which type of gateway would be required?
A.voice gateway
B.digital trunk gateway
C.analog trunk gateway
D.digital station gateway
Answer: B
Explanation:
This question is to examine the gateway types.
Voice gateway is generally used to connect different types of voice networks. The digital trunk gateway is used to connect CUCM system and PBX or the PSTN network. The using signaling is generally PRI CSS or T1/E1 CAS. The analog trunk gateway can be used to connect IP voice networks, analog phone, and fax. The digital station gateway is applicable to connect IP phones and IP voice networks. Choose B.

Question 20
Place the steps for inbound dial-peer matching in the correct order.
(1)If no matches are found, the system uses the default dial peer.
(2)Look for the destination-pattern command in a dial peer that matches the calling number or ANI string of the incoming call leg.
(3)Look for the POTS dial peer port configuration that matches the voice port associated with the incoming call(POTS dial peers only)
(4)Look for the incoming called-number command in the dial peer that matches the called number or DNIS string in the inbound call leg.
(5)Look for the answer-address command in a dial peer that matches the calling number or ANI string of the inbound call leg.
(I)Step1
(II)Step2
(III)Step3
(IV)Step4
(V)Step5
A.
(I)-(4);(II)-(2);(III)-(5);(IV)-(3);(V)-(1)
B.
(I)-(4);(II)-(5);(III)-(2);(IV)-(3);(V)-(1)
C.
(I)-(5);(II)-(4);(III)-(2);(IV)-(3);(V)-(1)
D.
(I)-(4);(II)-(5);(III)-(2);(IV)-(1);(V)-(3)
Answer: B
Explanation:
This question is to examine the steps for inbound dial-peer matching.
1. Looking for the incoming called-number command to match the called number;
2. Looking for the answer-address command to match the calling number;
3. Looking for the destination-pattern command to match the calling number;
4. Looking for the POTS dial peer port configuration to match the voice port;
5. If no matches are available, the system uses the default dial peer.